In the catalyst regenerator of a fluid catalytic cracking unit there is typically positioned one or more pipe headers fitted with a plurality of nozzles for distributing regeneration gas into the bed of spent catalyst. These pipe headers are frequently but not necessarily shaped in a ring configuration and supplied by a regeneration gas supply header entering the vessel from below as illustrated in U.S. Pat. Nos. 3,912,460 and 4,443,551 both incorporated herein by reference.
These pipe headers called air distributors are supported in the vessel and since the distributor temperature is high, approaching the process temperature (1100.degree. to 1400.degree. F.), and the shell temperatures are low (200.degree. to 400.degree. F.); protected by insulation, the air distributor support assembly must be able to compensate for considerable thermal expansion between the air distributor apparatus, air supply header, vessel supporting structure and supporting elements.
The air distributor support assembly shown in U.S. Pat. No. 4,101,288; incorporated herein by reference, solved a number of problems associated with thermal expansion experienced in air distributors. This was accomplished, as shown in FIG. 1 of the patent by alignment of pivotally mounted support members to allow for movement and recovery from differential thermal expansion. The direction of thermal expansion induced motion must be predicted when using this assembly to achieve the best alignment of this apparatus. The present invention is an improvement in that it renders such alignment unnecessary, and still compensates for air distributor expansion, warping and twisting.